There are many conditions which may result in a person becoming partially or completely edentulous (periodontal disease, an injury, etc.), which in the past had been remedied by the wearing of a prosthetic device known as dentures. Dentures were constructed to replace the missing teeth and were supported by surrounding teeth and/or by the underlying tissue. The significant drawbacks to the wearing of such partial or complete dentures, principally its means of support, which often required the use of adhesives and its cleaning requirements, had served to bolster the development of dental implants.
Dental implants may be subperiosteal, being placed on top of the bone and beneath the periostium—the fibrous membrane covering the jaw bones—and may have posts protruding through the gum to support a prosthesis. Alternatively, a dental implant may be endosteal (in the bone—endosseous), being a “root” device that is usually made of titanium, which is inserted into the jaw through the bone at the alveolar ridges. A healing period on the order of months is necessary for osseointegration, during which time the bone will grow in and around the implant to provide support that may exceed that of the natural tooth. After the healing period, an abutment may be attached thereto and may protrude through the periostium and gingival tissues to receive a prosthodontic appliance—a new tooth. Endosteal implants are used within wide and deep bone, or bone at least wide enough for their placement. Where the jaw bone is too narrow and not a good candidate for endosseous implants, a subperiosteal implant may be utilized. However, the subperiosteal implant technique is seldom used today.
The alveolar ridges are columns of bone, found on both the maxilla and the mandible, that surround and anchor the teeth within sockets known as alveoli. However, the alveolar bone quickly becomes atrophic in the absence of teeth, resulting in lack of available bone. In the Maxilla, sinus pneumatization decreases available bone after tooth loss, requiring a sinus elevation procedure prior to implant placement. Studies have shown the bone loss to be progressive. In many cases where a patient's jaw bone may have become too shallow or narrow for an endosteal implant, a sinus lift procedure may be performed to increase the amount of bone in the maxilla. The sinus lift procedure may be performed either through a lateral approach or a crestal approach.
In the crestal approach for a sinus lift procedure of the posterior maxilla (upper jaw), to which the improvements of the present invention is directed, a pilot drill may initially be used to create a small hole to form an implant insertion axis. The depth of penetration by the drill may be limited, by a stop or guide that is set using x-rays of the crestal area, so as to be within 1-2 mm of the sinus floor. The anatomical characteristics of the posterior maxilla, particularly the existence of its more spongy (cancellous) bone, enable it to successfully lend itself to undergo the ridge expansion osteotomy technique developed by R. B. Summers, which was published in 1994 (see e.g., Summers, D M D, Robert B, “A New Concept in Maxillary Implant Surgery: The Osteotome Technique;” 1994; Summers, D M D, Robert B, “The Osteotome Technique: Part 2—The Ridge Expansion Osteotomy (REO) Procedure;” 1994; and Summers, D M D, Robert B, “The Osteotome Technique: Part 3—Less Invasive Methods of Elevating the Sinus Floor;” 1994).
The technique causes expansion of the pilot hole without further elimination of bone material, and generally compresses the bone and increases bone density, in the surgeon's favor. The technique uses a succession of conical expansion Osteotome tools having a gradual diameter escalation. The smallest caliber expansion Osteotome tool is inserted manually into the pilot hole, with pressing and rotating of the tool occurring until the desired depth is reached, or until further penetration is resisted, at which time gentle tapping using a surgical mallet on the Osteotome may cause it to reach the proper depth. Further use of successively larger Osteotome tools causes lateral compression that increases bone density and the size of the opening. The different calibers of Osteotomes may be constructed such that the initial diameter of a successively larger Osteotome is the same as the largest penetrating diameter of the previous conical Osteotome that was used, thereby providing a constant progression of increasing separation.
During the expansion of the opening, with its resulting bone compression using the succession of Osteotomes, care must be taken as to the depth of penetration by the tools, to avoid puncturing of the sinus membrane. Once sufficient expansion and compaction has occurred for the intended implant, the cortical bone layer of the inferior sinus wall (floor) may be intentionally breached using the Osteotome, while exercising diligence to again avoid damage to the sinus membrane. The membrane is then typically detached in a gentle manner and displaced inwardly (lifted) using the Osteotome to working height. The space caused by the displacement of the membrane that had been overlying the sinus floor may then be packed with small donor bone particles using a larger diameter tool. The particles become part of the patient's jawbone during the osseointegration process. The implant is generally inserted into the new “socket” immediately, when enough bone height is present to achieve good primary fixation. If there was initially insufficient bone between the upper jaw ridge and the sinus membrane to provide adequate stability for the implant, the sinus augmentation and implant placement may need to be performed in separate procedures, being separated by the passage of several months.
There are many steps taken during the performance of this procedure during which serious damage may be caused to the patient's physiology, particularly with respect to the sinus membrane. Puncturing of the membrane is a serious complication, which may be worsened by the introduction of bone particles therein, and the contracting of a fungal infection could furthermore be fatal. In addition, when a perforation occurs, the bone particle may lead to blockage of the osteum and cause sinusitis. If membrane repair cannot be carried out, the procedure should be aborted prior to bone placement. Membrane repair during the crestal approach is very difficult to achieve.
The prior art Osteotomes have sought to improve the procedure, but are nonetheless still lacking. For example, U.S. Patent Application Pub. No. 2009/0292288 by Hung discloses that “tip members . . . with different styles and sizes” may be replaceable “by a mechanical manner such as screwing.” While constituting an improvement, it does not go far enough to assist the oral surgeon seeking to perform implant surgery on a patient in a brief amount of time, and in the safest manner according to his/her own physique and preferences. The present invention improves upon the Hung application.
The various improvements offered by the present invention serve to reduce the number of Osteotomes that are required by the oral surgeon, and additionally provide new apparatus that increase safety as to preventing the perforation of the sinus membrane, and for performing the sinus lift procedure.